It is widely assumed that fetal ischemic brain injury during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia, however, is one of several c...It is widely assumed that fetal ischemic brain injury during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia, however, is one of several causes of perinatal neurological injury and may not be the most common;most neonates diagnosed with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia. Sepsis, direct brain trauma, and drug or toxin exposure account for some cases, while mechanical forces of labor and delivery that increase fetal intracranial pressure sufficiently to impair brain perfusion may also contribute. Because of bony compliance and mobile suture lines, the fetal skull changes shape and redistributes cerebrospinal fluid during labor according to constraints imposed by contractions, and bony and soft tissue elements of the birth canal as the head descends. These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient descent of the head while safeguarding cerebral blood flow. Autonomic reflexes mediated through central receptors normally provide ample protection of the brain from the considerable pressure exerted on the skull. On occasion, those forces, which are transmitted intracranially, may overcome the various adaptive anatomical, cardiovascular, metabolic, and neurological mechanisms that maintain cerebral perfusion and oxygen availability, resulting in ischemic brain injury. Accepting the notion of a potentially adverse impact of fetal head compression suggests that avoidance of excessive uterine activity and of relentless pushing without steady progress in descent may offer protection for the fetal brain during parturition. Excessive head compression should be considered in the differential diagnosis of ischemic encephalopathy.展开更多
Neuro D plays a key regulatory effect on differentiation of neural stem cells into mature neurons in the brain.Thus,we assumed that electroacupuncture at Baihui（DU20） acupoint in newborn rats exposed to in utero fet...Neuro D plays a key regulatory effect on differentiation of neural stem cells into mature neurons in the brain.Thus,we assumed that electroacupuncture at Baihui（DU20） acupoint in newborn rats exposed to in utero fetal distress would influence expression of Neuro D.Electroacupuncture at Baihui was performed for 20 minutes on 3-day-old（Day 3） newborn Sprague-Dawley rats exposed to in utero fetal distress;electroacupuncture parameters consisted of sparse and dense waves at a frequency of 2–10 Hz.Real-time fluorescent quantitative PCR results demonstrated that m RNA expression of Neuro D,a molecule that indicates Neuro D,increased with prolonged time in brains of newborn rats,and peaked on Day 22.The level of m RNA expression was similar between Day 16 and Day 35.These findings suggest that electro acupuncture at Baihui acupoint could effectively increase m RNA expression of molecules involved in Neuro D in the brains of newborn rats exposed to in utero fetal distress.展开更多
文摘It is widely assumed that fetal ischemic brain injury during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia, however, is one of several causes of perinatal neurological injury and may not be the most common;most neonates diagnosed with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia. Sepsis, direct brain trauma, and drug or toxin exposure account for some cases, while mechanical forces of labor and delivery that increase fetal intracranial pressure sufficiently to impair brain perfusion may also contribute. Because of bony compliance and mobile suture lines, the fetal skull changes shape and redistributes cerebrospinal fluid during labor according to constraints imposed by contractions, and bony and soft tissue elements of the birth canal as the head descends. These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient descent of the head while safeguarding cerebral blood flow. Autonomic reflexes mediated through central receptors normally provide ample protection of the brain from the considerable pressure exerted on the skull. On occasion, those forces, which are transmitted intracranially, may overcome the various adaptive anatomical, cardiovascular, metabolic, and neurological mechanisms that maintain cerebral perfusion and oxygen availability, resulting in ischemic brain injury. Accepting the notion of a potentially adverse impact of fetal head compression suggests that avoidance of excessive uterine activity and of relentless pushing without steady progress in descent may offer protection for the fetal brain during parturition. Excessive head compression should be considered in the differential diagnosis of ischemic encephalopathy.
基金supported by the Natural Science Foundation of Fujian Province of China,No.2015J01133the Professor Academic Development Foundation of Fujian Medical University of China,No.JS11003
文摘Neuro D plays a key regulatory effect on differentiation of neural stem cells into mature neurons in the brain.Thus,we assumed that electroacupuncture at Baihui（DU20） acupoint in newborn rats exposed to in utero fetal distress would influence expression of Neuro D.Electroacupuncture at Baihui was performed for 20 minutes on 3-day-old（Day 3） newborn Sprague-Dawley rats exposed to in utero fetal distress;electroacupuncture parameters consisted of sparse and dense waves at a frequency of 2–10 Hz.Real-time fluorescent quantitative PCR results demonstrated that m RNA expression of Neuro D,a molecule that indicates Neuro D,increased with prolonged time in brains of newborn rats,and peaked on Day 22.The level of m RNA expression was similar between Day 16 and Day 35.These findings suggest that electro acupuncture at Baihui acupoint could effectively increase m RNA expression of molecules involved in Neuro D in the brains of newborn rats exposed to in utero fetal distress.
